A terrible murder may be committed on the grounds of Nankai Academy. Professor Yuko, one of many school's hottest teachers, died when she was pushed off of the roof of one of many school's buildings. Her death leaves her students with feelings of confusion, pain, and most importantly... anger. Four of her male students, Masayoshi, Daisuke, Mitsuru and Shinya, are determined to uncover the truth. They soon discover an important clue: Professor Yuko's planner was marked on the very night she was killed... marked using the names of seven girls.

With this evidence, the boys begin their investigations... and they'll use any method required and discover the murderer. Through rape, manipulation and torture, they uncover important details, but piecing the puzzle together won't be simple. Along with the longer their search draws on, the harder they think themselves being overtaken by their very own dark desires... Would they ever get the truth behind Yuko's death?